Search

Ultralow oil-water interfacial tension (IFT) has provided an important basis for screening optimum surfactant formulation for improving the oil washing efficiency. Thus, it is of great significance to further investigate the selection method for surfactant systems with ultralow IFT. In this study, a selection of surfactant systems with ultralow IFT was simplified by a method of comparing the equivalent alkane carbon number (EACN) of crude oil with the minimum alkane carbon number (n min) of surfactant mixtures. The results show that the ultralow IFT can be achieved when the n min of optimum surfactant formulation is equal to the EACN of crude oil. Meanwhile, the oil washing efficiency experiments show that the oil washing efficiency increases with the decrease of IFT, and the optimum surfactant formulation with ultralow IFT has the highest oil washing efficiency. This study provides a more efficient way for selecting optimum surfactant formulation systems with ultralow IFT for improving the oil washing efficiency.

In H2, CO2 and natural gas geo-storage, rock-fluid interfacial tension ( γ r o c k − f l u i d ) is a key parameter which influences pore-scale fluid distribution and reservoir-scale gas storage capacity and containment security. However, γ r o c k − f l u i d data is seriously lacking because of the inability to measure this parameter experimentally. Therefore herein, a semi-empirical method is used to calculate γ r o c k − f l u i d at geo-storage conditions. Additionally, effects of organic acid and silica nanofluid on γ r o c k − f l u i d are studied. The following results are obtained. γ r o c k − g a s decreases with pressure, temperature, organic acid concentration and carbon number increase, while γ r o c k − H 2 O increases with organic acid concentration and carbon number increase; γ r o c k − g a s first increases and subsequently decreases with silica nanofluid concentration increase, while γ r o c k − H 2 O first decreases and then increases with silica nanofluid concentration increase; for same thermo-physical and rock surface chemistry conditions, γ r o c k − g a s follows the order H2 > CH4 > CO2. These insights provide pivotal guidance on gas geo-storage and thus aids in the implementation of a more sustainable energy supply chain.

Cooking emissions account for a major fraction of urban organic aerosol. It is therefore important to understand the atmospheric evolution in the physical and chemical properties of organic compounds emitted from cooking activities. In this work, we investigate the formation of secondary organic aerosol (SOA) from oxidation of gas-phase organic compounds from heated cooking oil. The chemical composition of cooking SOA is analyzed using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). While the particle-phase composition of SOA is a highly complex mixture, we adopt a new method to achieve molecular speciation of the SOA. All the GC-elutable material is classified by the constituent functional groups, allowing us to provide a molecular description of its chemical evolution upon oxidative aging. Our results demonstrate an increase in average oxidation state (from −0.6 to −0.24) and decrease in average carbon number (from 5.2 to 4.9) with increasing photochemical aging of cooking oil, suggesting that fragmentation reactions are key processes in the oxidative aging of cooking emissions within 2 d equivalent of ambient oxidant exposure. Moreover, we estimate that aldehyde precursors from cooking emissions account for a majority of the SOA formation and oxidation products. Overall, our results provide insights into the atmospheric evolution of cooking SOA, a majority of which is derived from gas-phase oxidation of aldehydes.

Nanotechnology plays an important role to increase food production by improving plant performance. Specifically, nanostructured lipid carriers (NLCs) are an important tool for the controlled release of compounds in agriculture. Furthermore, volatile organic compounds (VOCs) have shown an important growth-inducing effect in vegetables. Nevertheless, there is no tool designed for VOC application in agricultural systems. Therefore, the study proposes the use of NLC to the controlled release of VOC to apply in horticulture. The focus of this study was to evaluate the direct impact of 2-ketones released from NLC on Solanum lycopersicum cv Marglobe and Lactuca sativa cv Reina de Mayo. NLCs synthesized with glyceryl tristearate and isopropyl myristate were characterized and used to encapsulate 250 ppm of 2-nonanone, 2-undecanone, or 2-tridecanone. Then, seedlings of S. lycopersicum and L. sativa were exposed to 2-ketones released from NLC for 10 days. Electrolyte leakage, anthocyanin, mass percentage, stomatal aperture, and chlorophyll fluorescence were measured. The data indicated that NLC had a mean size of 205 nm and homogeneity. NLC showed a capacity for the controlled release of 2-ketones, depending on the carbon number of the encapsulated compound. The release of 2-ketones did not have a significant effect on electrolyte leakage and anthocyanin content, but they modulate the percentage of surface elements. The role of 2-ketones to increase stomata aperture and chlorophyll concentration is noted. The results strongly suggest that NLCs are potential carriers for the release of bioactive compounds with potential use in agriculture.

Two series of supports, SAPO-11 (Si/Al: 0–0.4) and alumina-coated SBA-15 (Al2O3: 0–20 wt %), with different pore structures were synthesized. Subsequently, the PtSn bimetallic catalysts supported o...

A sugar-based, low-molecular-weight gelator 16AG, can gelatinize primary alcohols by forming supramolecular fibers. We obtained non-helical, tape-like fibers in methanol and ethanol but helical fibers in alcohols with at least three carbons. The pitch of the helical fibers became shorter with increasing carbon number.

Bovine milk is a complex mixture of lipids, proteins, carbohydrates, and other factors of which lipids comprise 3-5% of the total mass. Rapid analysis and characterization of the triacylglycerols (TAG) that comprise about 95% of the total lipid is daunting given the numerous TAG species. In the attached methods paper, we demonstrate an improved method for identifying and quantifying TAG species by infusion-based "shotgun" lipidomics. Because of the broad range of TAG species in milk, a single internal standard was insufficient for the analysis and required sectioning the spectrum into three portions based upon mass range to provide accurate quantitation of TAG species. Isobaric phospholipid interferences were removed using a simple dispersive solid-phase extraction step. Using this method, > 100 TAG species were quantitated by acyl carbon number and desaturation level in a sample of commercially purchased bovine milk.

Since its introduction in 1957 the Flame Ionization Detector (FID) is the most widely used Gas Chromatographic (GC) detector. Nowadays there is no Gas Chromatographic laboratory without apparatus containing a Flame Ionization Detector. However, the operation mechanism of the hydrogen flame and signal production is still not completely obvious. The FID response for hydrocarbons is proportional to the carbon content of the compound, while substances that contain heteroatoms yield smaller responses. In the Gas Chromatographic practice, a special relative response factor called Effective Carbon Number (ECN) is used for the expression of the response for molecules containing heteroatom. In the literature there are signal modifying constants published by different authors, which are typical of the carbon atoms and heteroatoms in the different chemical bonds. Although these constants express the nature of the modification (increase or decrease) the exact modifying value always depends on the chromatographic parameters and the molecular structure. If we want to apply the ECN method for our calculations these constants should be determined for our specific Gas Chromatographic system. In our earlier study we investigated the effect of the temperature of the injector, column and detector, the mode of the injection and the concentration level of the substance. The aim of this paper is to investigate the effect of the linear velocity on the response of the Flame Ionization Detector as a mass flow rate sensitive detector in the case of capillary column.

Hydrophobization of cellulose by grafting with fatty acid chlorides varies depending on the fatty acid carbon number (i.e., the length of the alkyl chain). In this study, we investigated the effect of fatty acid chain length on cellulose hydrophobization by gas grafting using fatty acid chlorides with carbon numbers ranging from C6 to C16. In addition, hydrophobization efficiencies were analyzed in relation to single and combination treatments using the different fatty acid chlorides. We discovered that paper hydrophobicity increased as the fatty acid carbon number increased during gas grafting. With the exception of dual treatment with C10 and C16, we found that dual treatment with fatty acid chlorides did not improve hydrophobization efficiency compared to single treatment during gas grafting. In conclusion, it was determined that carbon number of the fatty acid is a main factor for gas grafting efficiency. Further, dual treatment with C10 and C16 fatty acid chlorides improved hydrophobization efficiency slightly more than that found from single treatment with C16 fatty acid chloride, but not at a sufficient level to recommend as an improved approach.

The hydrogenation of C7-C9 olefins, which lead to severe loss of octane number in hydrodesulfurization (HDS) process of gasoline, was investigated. The hydrogenation activity of olefins was also af...

In this study, cored sediment samples collected by the Jiaolong Submersible at 6 779 m depth from the hadal zone of the Yap Trench in May 2016 were sliced in 1-cm interval from top to bottom, and lipids in each sediment layer were quantitatively and qualitatively analyzed. The vertical distribution profiles of the lipids in the sediment sample, their main existing forms, and their possible sources were investigated. The results show that the concentration of lipid in the surface sediment was the highest with the carbon number from 12 to 27, dominated by medium and short-chain lipids. The total concentration of fatty acids in surface sediment was much higher than those in the offshore and deep-sea areas, being up to 325.77 μg/g due to the funnel effect caused by the “V” terrain of the trench. Fatty acid 18.0 was the most abundant lipids in the sediment sample. Abnormal high concentrations of fatty acid 18.ω7 and alkanes indicated the existence of hydrothermal fluids in the study area. In addition, saturated fatty acids and monounsaturated fatty acids existed mainly in free form, and polyunsaturated fatty acids existed mainly in bound form. Most of the alkanes were in bound form, and their major source was autochthounous input. The carbon number of alcohols in the sediment sample ranged from 12 to 20, mainly existed in bound form. The source of fatty acids was mainly autochthonous input, and the neutral lipids had both marine and terrestrial origin. This is the first study of lipids in hadal sediment of the Yap Trench. The results will promote deeper understanding of organic carbon cycle in marine environment.

Total lipids, fatty acids and triacylglycerols in seeds of the four Saudi Arabian date cultivars ‘Anbra’, ‘Megadwel’, ‘Sacai’ and ‘Sfwai’ were analysed. Total lipid contents ranged between 7.3 and 8.6%. Oleic, lauric and myristic acid represented the most abundant fatty acids in date seed oil. HPLC‐DAD‐ESI‐MSⁿ analysis enabled the identification of 40 triacylglycerols with equivalent carbon number (ECN) 36–54, of which 17 were detected for the first time. Triacylglycerols mainly comprised LaOL, LaLaL, LaML, MML/LaPL and LaOO. ‘Anbra’ oil was characterised by highest proportions of saturated fatty acids and triacylglycerols with ECN 36 and 48–54. Unsaturated fatty acids prevailed in the three remaining varieties. Elevated proportions of triacylglycerols with medium ECNs were found in ‘Megadwel’ and ‘Sfwai’ oils. Aside from highest total lipid contents, ‘Sacai’ seeds predominantly contained triacylglycerols with low ECNs. Multivariate statistical analyses elucidated varietal influences on the fatty acid and triacylglycerol composition of date seed oil.

The solubilities of water in various hydrocarbons are usually needed to assess the water content in oil products. Because the solubilities of water in hydrocarbons are very small, which usually leads to large deviations in experiments, and because we have trouble carrying out experiments on bulk hydrocarbons, it is necessary to develop a more convenient molecular simulation approach to predict the solubility. In this paper, COSMO-RS, a statistical thermodynamic method based on quantum chemistry, has been employed to obtain the solubilities of water in n-alkanes, alkylcyclohexanes, alkylbenzenes and 1-alkenes by calculating the difference of the thermodynamic properties during the dissolution process. The predictions of COSMO-RS were compared with the experimental data, as well as those of API correlations and the Tsonopoulos correlation. The results indicate that COSMO-RS can better predict the trends of the solubility with high accuracy, where the deviations are within ± 29.41%. The characteristics of the solubilities of water in various hydrocarbons are interpreted systemically, especially for the influence of carbon number, CN. It particularly focuses on the non-monotonicity of the solubility curves of water in n-alkanes with the increase of CN. In addition, the effect of temperature on the characteristic of solubility is simultaneously investigated.

Spilled oil is highly susceptible to sunlight-induced transformations, both as films on the surface of water and material dissolved or dispersed in the water column. We utilized ultrahigh-resolutio...

With regard to speed, comfort, and a dense network of destinations, the popularity of air transport is on the rise. For this reason, jet fuel is a commodity with rapidly growing consumption and interesting refinery margins. At the same time, however, it is becoming a focus of attention in terms of reducing negative environmental impacts. As a response to these trends, it will be necessary to coprocess alternative petroleum fractions with sustainable aviation components in oil refineries. Six alternative jet fuel samples of different origin were used to investigate their jet fuel-specific properties, that is, aromatics (from 0 to 59.7 vol%), smoke point (from 12.2 to >50 mm), freezing point (from −49 to 50 mm) and freezing point (

This contribution presents an extensive literature survey of the calorimetric properties, namely enthalpy and entropy of fusion, of alkyl‐based molecules. Building on the well‐known linear correlation of the named properties to the carbon number in n‐alkanes, saturated fatty acids (FA), and saturated monoacid triglycerides (TAGs), the calorimetric properties of TAGs are reviewed. No straightforward correlation using a single ordering parameter, i.e., carbon number, can be derived for TAGs. This is not surprising due to the complexity of this particular class of molecules differing in alkyl‐chain distribution over the glycerol backbone and chain saturation. A linear correlation of enthalpy and entropy of fusion is evident for molecule classes for which both properties correlate linearly with the carbon number, e.g., n‐alkanes. Despite the complexity of TAGs, it is possible to establish a linear correlation between enthalpy and entropy of fusion even though no underlying single ordering parameter can be identified. A linear fit reveals discrepancies between saturated and unsaturated molecules but independence of polymorphic forms and chain length differences in mixed‐acid TAGs. Moreover, the slopes of the linear fits for data on n‐alkanes, saturated FA, and saturated mono‐acid TAGs are found to be in the vicinity of the melting temperature of polyethylene.

N-Substituted derivatives of 1,4-dideoxy-1,4-imino-d-mannitol (DIM), the pyrrolidine core of swainsonine, have been synthesized efficiently and stereoselectively from d-mannose with 2,3:5,6-di-O-isopropylidene DIM (10) as a key intermediate. These N-substituted derivatives include N-alkylated, N-alkenylated, N-hydroxyalkylated and N-aralkylated DIMs with the carbon number of the alkyl chain ranging from one to nine. The obtained 33 N-substituted DIM derivatives were assayed against various glycosidases, which allowed a systematic evaluation of their glycosidase inhibition profiles. Though N-substitution of DIM decreased their α-mannosidase inhibitory activities, some of the derivatives showed significant inhibition of other glycosidases.

The main aim of this paper is to establish a correlation for prediction the thermal conductivity of n-alkanes within a give temperature range for homologous n-alkanes series from CH4 to C30H62. The predicted thermal conductivity values depend on the temperature and carbon number for each alkanes component. This paper describes a method of predicting the thermal conductivity of any alkanes between the temperature range, based on a measurement of the thermal conductivity. Where prediction are based on lower temperature measurements, where the accuracy is generally better then 3.1% for 178 data points. Useful predictions can also be made from any temperature measurements for most alkanes, but with reduced accuracy. This method permits alkanes to be used in situations where the thermal conductivity is important without having to make (or find) direct measurements over the entire temperature range of interest. Recommended thermal conductivity values are presented for 30 components.

A series of Monomethyl branched alkanes compounds were detected between nC14–nC36, in immature and low maturity Jurassic humic coal, Junggar basin. 2-methyl alkanes and 3-methyl alkanes accounted for the vast majority of the compounds. It is worth noting that the 2-methyl alkanes in the humic coal samples show an obvious distribution of even carbon predominances rarely reported in the literature. The results show that with the increase of Pr/Ph (pristane/phytane), the even carbon dominance of 2-methyl alkanes is more obvious, while the odd carbon number distribution of 3-methyl alkanes is weakened. As Pr/Ph increases in the humic coal, the relative content of the hopanes increased, while the relative content of 2-methyl alkanes and 3-methyl alkanes increases first and then decreases.

We present direct room-temperature vapour pressure measurements for eight semi-volatile n-alkanes of atmospheric importance. Measured vapour pressures range from 8.4 ± 1.6 × 10−3 Pa for C17, to 1.7 ± 0.6 × 10−8 Pa for C31. The new measurements for C17–C18 are in reasonable agreement but at the lower end of values in the literature; the new measurements for C28 and C31 are one-to-two orders of magnitude higher than most literature values, but six orders of magnitude higher than the lowest values in the literature. Our measurements are suitable for atmospheric aerosol modelling and interpretation of environmental measurements, interpolated in carbon number where necessary, and extrapolated over temperatures relevant to the atmospheric boundary layer using the Clausius-Clapeyron equation with literature values of the enthalpy of vaporisation.

Fitted functions that correlate binary interaction parameters (BIP) for the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) with the carbon number of n-alkane...

In this research, the oxidation behavior of six linear and branched alkanes was investigated using high-pressure differential scanning calorimeter (HP-DSC) and thermogravimetry coupled with Fourier-transform infrared spectroscopy (TG-FTIR) to compare the similarities and differences between branched and linear alkanes. The results indicated that both branched and linear alkanes showed only low-temperature oxidation (LTO), which implies that alkanes barely contribute in coke formation and thus no obvious high-temperature oxidation (HTO) was observed as no enough fuel was deposited. The LTO of linear alkanes seems to be independent of their carbon number, which, however, does not apply to branched alkanes. The oxidation behavior of branched alkanes was different from their linear chain counterparts due to the effect of their different molecule structure. Branched alkanes reacted earlier and faster at initial stage relative to their linear chain counterparts, but their reaction rates became slower at later stage with the increase of temperature. Branched alkanes can produce some oxidized compounds with C O group, while linear alkanes can form more carbonyl groups and some oxidized compounds (like carboxylic acids) that can help to produce more CO2 by decomposition.

Turpan-Hami Basin is a major petroliferous basin in China. To date the natural gas exploration is concentrated in the Taibei sag. The origin and source of natural gas in the Taibei sag has long been controversial. To further investigate the origin and source of the natural gas in the Taibei sag, combined with previous studies and the local geological backgrounds, this study collected 23 gas samples from the Baka, Qiuling, Shanshan and Wenmi oil fields in the Taibei sag and analyzed the sample composition, stable carbon and hydrogen isotopes of all the gas samples. The results show that, gases from the four oil fields in the Taibei sag are dominated by hydrocarbon gas and belong to wet gas. Methane accounts for 65.84% to 97.94%, the content of heavy hydrocarbon (C2-5) can be up to 34.98%, while the content of nonhydrocarbon (CO2, N2) is trace. The δ13C1 value is –44.9‰ to –40.4‰, δ13C2 is –28.2‰ to –24.9‰, δ13C3 is –27.1‰ to –18.0‰ and δ13C4 is –26.7‰ to –22.1; while the variation of δD1 is not significant from –272‰ to –252‰, δD2 is –236‰ to –200‰ and δD3 is –222‰ to –174‰. Methane and its homologues (C2-5) are characterized by normal stable carbon and hydrogen isotopic distribution pattern, i.e., with the increase of carbon number, methane and its homologues become more and more enriched in 13C or D (δ13C1

The composition and distribution of hydrocarbons in the initial solvent extracts (bitumen I) and corresponding secondary extracts (bitumen II) of kerogens in the Lower Cambrian marine shales from Guizhou Province of South China, were comparatively studied. The goal of this study is to explore whether the secondary extracts can provide the compensatory information on the source inputs of original organic matters, depositional environments and thermal maturity in highly mature shales. The results show that their similarities are mainly reflected by the same components of hydrocarbons, such as n-alkanes, acyclic isoprenoids, terpanes, and steranes detected in two bitumen fractions. These similarities suggest that the hydrocarbons in bitumens I and II are generally indigenous. Whereas the relative abundances of tricyclic terpanes (TT) and diginanes are significantly high in bitumen II, as their ratios of C21TT/αβC30 hopane and C21/20R αααC27 sterane in bitumen II are much higher than those in bitumen I. Bitumen II is also characterized by a relatively higher abundance of low carbon number alkanes as the C21−/C22+ ratios in the range of 8.4–31.5 contrasted to 0.9–5.2 in bitumen I. The hydrocarbons and their related ratios indicate that bitumen II had reserved some intact features of the initial hydrocarbon composition, and therefore may provide useful information on the source input and thermal maturity of organic matters in the highly mature sediments, whose initial soluble organic matters were heavily degraded and/or overprinted.

We have collected data on the proton-transfer reactions with H3O+ ions for trace gas detection into an online and publicly available library. The library allows users of proton-transfer-reaction mass spectrometry (PTR-MS) and selected-ion flow-tube mass spectrometry (SIFT-MS) to look up at which m/z a trace gas of interest is detected. Vice versa, the library also allows looking up what trace gas may have been responsible for a product ion detected in PTR-MS and SIFT-MS. Finally, the library may serve as a dataset for further research on calculating instrument sensitivity and product-ion fragmentation, improving identification and quantification of newly detectable compounds as advances in instrumentation continue. To demonstrate the utility of the library, we present a brief analysis of product-ion fragmentation. We show that oxygenated organic compounds exhibit trends in neutral loss according to their functionality, and that on average neutral losses decrease the carbon number and increase the extent of unsaturation of product ions. Graphical Abstract.

The oil recovery reservoirs and oil trapping in the reservoirs are extensively function of interfacial tension between brine and hydrocarbon, so estimation of interfacial tension becomes one of the interesting topics in petroleum industry. In this study, Grid partitioning based Fuzzy inference system method is utilized to forecast interfacial tension of hydrocarbon and brine based on various effective parameters such as ionic strength of brine, carbon number of hydrocarbon, pressure, and temperature. The estimated values of interfacial tension were compared with real interfacial tension of brine and hydrocarbon using graphical and statistical analyses. The determined coefficients of determination (R2) for training and testing phases were 0.9916 and 0.9447, respectively. The comparing analyses express that the Grid partitioning based Fuzzy inference system method has great ability in prediction of interfacial tension, and it can be used as an applicable tool in petroleum industry.

The Maillard reaction accompanying the baking of bread largely affects the quality of finished bread and the degree of taste. Particularly, the difference of lipids as a secondary material can be considered as one of the major factors. We examined how the differences in constituent fatty acids of lipids in secondary materials are related to Maillard reaction. Chemical differences in added fatty acids were identified to be a major factor in the induction of the Maillard reaction and lipid peroxidation in bread baking. With saturated fatty acids, a higher carbon number tended to promote the Maillard reaction induction and suppress lipid peroxidation induction. Conversely, with unsaturated fatty acids, a greater degree of unsaturation tended to suppress the Maillard reaction induction and promote lipid peroxidation induction. The present findings clarified the involvement of fatty acid carbon number and degree of unsaturation in the Maillard reaction and lipid peroxidation inductions in bread baking. This phenomenon is a novel finding for the food science field.

The purpose of this research work is to determine the maximum single carbon number (SCN) which can be reliably quantified using High Temperature Gas Chromatography (HTGC) analysis of heavy oil hydrocarbons, accounting for (i) thermal cracking risk and (ii) the non/incomplete elution. To that end, an in-house coupled numerical Pyrolysis-GC model has been developed, capable of calculating the degree of elution and of simulating the migration, partitioning, and pyrolysis conversion of a mixture of 11 heavy n-alkanes spanning the range from nC14H30 to nC80H16 throughout the GC column. On the basis of this model and using a commonly used column configuration and temperature program, two conclusions have been made: (i) half of the mass injected of nC80 thermally decomposed before nC70 has eluted, suggesting a possible coelution of both nC70 and the pyrolysis products of nC80 and therefore making the HTGC analysis of nC70 and heavier n-alkanes no longer reliable, and (ii) alkanes heavier than nC70 take progressi...